This invention relates to a machining process determination method in automatic programming and, more particularly, to a machining process determination method whereby machining processes such as predrilling, rough cutting of outer diameter, outer diameter finishing, rough cutting of inner diameter, inner diameter finishing and end face cutting are stored in memory in the order of machining; the machining processes are read out of the memory successively in the order of machining; and NC data are created upon determining, based on blank profile data and final part profile data, whether a machining process is one necessary for obtaining a final part.
Automatic programming systems have come into practical use and are utilized to create NC tapes from a design drawing through a simple operation by entering data in a conversational mode using a graphic display screen. With such an automatic programming system, a machining profile can be entered merely by pressing profile symbol keys which are located on an operator's panel and correspond to workpiece profiles written on a design drawing. Further, according to the automatic programming system, referential information is graphically displayed on the screen from time to time and inquiries are made in ordinary language, so that dimensions and various data can be entered in response to the inquiries. When all data necessary for creation of an NC tape have been entered, the system immediately displays graphically the blank profile and the machined profile (finished profile), begins automatic calculation of NC command data and graphically displays a tool path to create an NC tape. A programming method performed by such an automatic programming system will now be described in detail. The method comprises the following steps:
(1) blank material selection step; PA1 (2) drawing mode selection step; PA1 (3) blank profile and dimensions input step; PA1 (4) machined profile and dimensions input step; PA1 (5) machine reference point and turret position input step; PA1 (6) machining process selection step; PA1 (7) tool selection step; PA1 (8) machining limits and cutting condition designation step; and PA1 (9) tool path calculation step.
The necessary data are entered successively to eventually create the NC data (NC tape).
In the input step for entering the blank profile and the dimensions thereof, a picture for entering the blank profile and its dimensions is displayed on the graphic display screen, so that one may enter the blank profile, its dimensional values and the position of a base line while observing what is displayed. Specifically, since blank profiles for turning machining are broadly classified into cylinders, hollow cylinders and special profile blanks, the images of these blanks and their menu numbers appear on the display screen, one of the blank profiles is selected from among the displayed blank profiles by entering its menu number, and then the dimensional values, namely the length L, thickness D, bore diameter D.sub.o and base line position ZP of the blank are entered. This completes the entry of the blank profile and its dimensional values.
The steps (6) through (8) are repeated until the final finished profile is obtained. Specifically, when it is turned for the machining process selection step, a prompt for selecting the machining process is displayed on the graphic display screen. Accordingly, depending upon the machining process which is to be performed, one enters the name of the desired machining process from among those being displayed on the screen. This is followed by entering the tool to be used in the entered machining process, as well as the cutting conditions, cutting direction and cutting area for the entered machining process.
Thereafter, when a different area is to be cut with the same tool, the fact is entered. Also entered are the cutting direction and the area. On the other hand, if it is unnecessary to cut a different area with the same tool, the fact is entered. Thus, when entry of data necessary for machining in accordance with the first machining process is completed, the operator decides whether a different machining process is required in order to obtain the final part profile (finished profile); if one is, the fact is entered. Thereafter, if machining process selection, entry of data indicative of the tool to be used, and entry of cutting conditions, cutting direction and cutting area are carried out in the above fashion until the finished profile is obtained, then all the necessary data will have been entered. An automatic programming unit then creates NC data on the basis of the input data and causes a tool trajectory to be displayed on the graphic display screen, thus ending programming.
Thus, in the NC data creation method as set forth above, the entry of blank profile and finished profile is followed by determining, based on the operator's judgment, in which area machining is to be performed and by which machining process, and in which cutting direction the tool is to be moved. In addition, the sequence of the machining processes is determined and the data necessary for the machining process sequence are entered. The method of this kind is extremely versatile since the programmer is capable of freely setting the machining process sequence, the machining area and the like. However, since considerable programmer judgment is required, the programming operation is a complicated one and, hence, errors are apt to made. Moreover, a long period of time is needed for programming.